Overweight and obesity are a cause of many non-communicable diseases leading to an increased risk of death. There are many programs aimed at weight reduction, but few publications have evaluated their effectiveness according to the gender and age of the subjects. The purpose of this study is to evaluate the effects of age and gender on weight loss outcomes in subjects participating in a 12-month online weight loss program. 400 subjects, 190 men and 210 women, were included in the study. The online intervention consisted of a 15% energy deficit diet and training (RESPO method). Changes in body weight over 12 months were similar (p = 0.14) across age groups. Weight reductions by month were statistically significant (p = 0.0001) in both groups. We noted no differences in weight loss between men and women expressed in kilograms. However, women reduced their body weight to a greater extent, i.e., by 2.7 percentage points, than men. Gender is a factor that may influence the effectiveness of weight loss programs, while age demonstrates no such influence. Our study shows that significant weight reduction during weight loss therapy is achieved by both men and women, but women can expect better results.
Keywords: energy restriction; gender; human; lose weight; men; obesity; online intervention; overweight; physical activity; women.